1. Field of the Invention
This invention relates to an improved lock assembly which incorporates a plurality of individual combination elements and means for detecting tampering with the lock assembly.
2. Description of the Prior Art
Lock assemblies incorporating a plurality of individual combination elements are shown in U.S. Pat. Nos. 1,448,888 to Walters, 1,612,778 to Meepos and 2,558,619 to Lehman. Basically, these systems operate in a manner such that if any one of the combination assemblies is not in proper position, the lock assembly will be maintained in a locked condition. Each of these assemblies operates to prevent relative rotation between two members when in a locked condition. It is one object of the present invention to provide a lock assembly having an improved multiple combination element configuration.
U.S. Pat. No. 942,553 to Hamilton discloses an assembly in which an exterior knob is normally decoupled from the interior knob and lock assembly. The lock assembly includes an axially movable push bar which may be selectively engaged with the exterior knob so as to enable the exterior knob to actuate the lock assembly. It is another object of the present invention to provide an exterior knob assembly which is selectively engageable with an interior lock mechanism.
Further objects of the invention are to provide a means for the detection of tampering with the lock assembly so as to increase the security of the unit, and to include components within the assembly which increase the difficulty of detection of the combination of the lock assembly.